Abstract: Most flapping-wing aircraft wings use a single degree of freedom to generate lift and thrust by flapping up and down, while
relying on the tail control surfaces to manage attitude. However, these aircraft have certain limitations, such as poor accuracy
in attitude control and inadequate roll control capabilities. This paper presents a design for an active torsional mechanism at
the wing's trailing edge, which enables differential variations in the pitch angle of the left and right wings during flapping.
This simple mechanical form significantly enhances the aircraft's roll control capacity. The experimental verification of this
mechanism was conducted in a wind tunnel using the RoboEagle flapping-wing aerial vehicle that we developed. The study
investigated the effects of the control strategy on lift, thrust, and roll moment during flapping flight. Additionally, the impact
of roll control on roll moment was examined under various wind speeds, flapping frequencies, angles of attack, and wing
flexibility. Furthermore, several rolling maneuver flight tests were performed to evaluate the agility of RoboEagle, utilizing
both the elevon control strategy and the new roll control strategy. The results demonstrated that the new roll control strategy
effectively enhances the roll control capability, thereby improving the attitude control capabilities of the flapping-wing
aircraft in complex wind field environments. This conclusion is supported by a comparison of the control time, maximum
roll angle, average roll angular velocity, and other relevant parameters between the two control strategies under identical
roll control input.